Accuracy in judgments of aggressiveness

Perceivers are both accurate and biased in their understanding of others. Past research has distinguished between three types of accuracy: generalized accuracy, a perceiver's accuracy about how a target interacts with others in general; perceiver accuracy, a perceiver's view of others corresponding with how the perceiver is treated by others in general; and dyadic accuracy, a perceiver's accuracy about a target when interacting with that target. Researchers have proposed that there should be more dyadic than other forms of accuracy among well-acquainted individuals because of the pragmatic utility of forecasting the behavior of interaction partners. We examined behavioral aggression among well-acquainted peers. A total of 116 9-year-old boys rated how aggressive their classmates were toward other classmates. Subsequently, 11 groups of 6 boys each interacted in play groups, during which observations of aggression were made. Analyses indicated strong generalized accuracy yet little dyadic and perceiver accuracy.     

Perceived orientation in depth from line-of-sight movement

Twelve college students viewed computer-generated displays of a cross comprised of two orthogonal dotted lines, and judged the apparent in-depth orientation of the horizontal arm by positioning a horizontal bar mounted on a rotary potentiometer. The vertical arm of the simulated cross was always in the observer’s frontal plane, but the randomly textured horizontal arm was in one of nine orientations relative to the line of sight. Each observer viewed displays in which the simulated cross was, alternately, (a) stationary, (b) approaching the viewer, and (c) stationary but expanding in size. The static texture density gradient in the horizontal arm of the simulated stationary cross mediated perceived orientation in depth. Further, when motion perspective was added to the detail perspective, the impression of depth was enhanced, with the greatest enhancement obtaining at the near viewing distance. When dynamic magnification was added to the detail perspective, the impression of depth was attenuated; this effect was interpreted as an illusory case of motion perspective.     

Accuracy of judgments of sexual orientation from thin slices of behavior.

In this research the authors examined the accuracy of judging sexual orientation on the basis of brief observations or "thin slices" of nonverbal behavior. In Study 1, sexual orientation was judged more accurately than chance, with judgments being more accurate when based on dynamic nonverbal behavior (10-s and 1-s silent video segments) than on static information (a series of 8 still photographs). Gay men and lesbians were more accurate than heterosexuals in judging still photographs and 1-s clips but not in 10-s clips. In Study 2, judgments based on 10-s dynamic figural outline displays containing primarily gestural information were more accurate than chance.     

Seeing versus imagining movement in depth

Subjects judged the quality of rigid motion between pairs of three-dimensional drawings that differed by a rotation in depth. The figures were aligned with, and rotated around, either the vertical axis or an axis that was oblique with respect to the XYZ co-ordinate system. Rated quality of motion decreased with increasing angular disparity between the figures and with decreasing stimulus duration, regardless of whether the figures were vertical or oblique. The same subjects then participated in a mental rotation task using the same stimuli and angular disparities. An effect of principal axis emerged, such that subjects took longer to make decisions about obliquely aligned stimuli than about vertically aligned stimuli, especially if they received the oblique stimuli first. These data imply that perceived versus imagined movement through the same trajectory involves different processes. Whereas the apparent motion system performs its computations relatively automatically, the processes involved in mental rotation are more strategic in nature.     

Development of depth perception mediated by motion parallax in unidimensional projections of rotation in depth.

Motion parallax is a composite of five transformations demonstrated to be effective in adult judgments of rotation direction in polar motion projections of a horizontal row of dots rotating in depth. The effectiveness of these transformations as a function of age was tested by presenting six such motion projections to first graders (age = 6 years), seventh graders (age = 13 years), and college students (age = 19 years). Identical age functions were obtained for judged rotation direction from the four motion projections representing (1) Velocity, corresponding to the traditional definition of motion parallax as differential velocity, (2) Velocity plus differences between ratios of instantaneous displacement to instantaneous acceleration for dots on the near and far sides of the rotation axis ($\text{D}\text{A}$ Difference), (3) Velocity, $\text{D}\text{A}$ Difference, and a gradient across the row of $\text{D}\text{A}$ ratios, and (4) all transformations. First graders, unable to use horizontal transformations, performed at chance on these four projections, while older students made correct judgments. Order, separated from Velocity for the first time, resulted in chance performance at all ages, while Direction, also separated from Velocity for the first time, resulted in veridical judgments in only 4 of 24 college students.     

Emergent two-dimensional patterns in images rotated in depth

Once a person has observed a three-dimensional scene, how accurately can he or she then imagine the appearance of that scene from different viewing angles? In a series of experiments addressed to this question, subjects formed mental images of a set of objects hanging in a clear cylinder and mentally rotated their images as they physically rotated the cylinder by various amounts. They were asked to perform four tasks, each demanding the ability to "see" the two-dimensional patterns that should emerge in their images if the images depicted the new perspective view accurately--(a) Subjects described the two-dimensional geometric shape that the imagined objects formed in an image rotated 90 degrees; (b) they "scanned" horizontally from one imagined object to another in a rotated image; (c) they physically rotated the empty cylinder together with their image until two of the imagined objects were vertically aligned; and (d) they adjusted a marker to line up with a single object in a rotated image. The experimental results converged to suggest that subjects' images accurately displayed the two-dimensional patterns emerging from a rotation in depth. However, the amount by which they rotated their image differed systematically from the amount specified by the experimenter. Results are discussed in the context of a model of the mental representation of physical space that incorporates two types of structures, one representing the three-dimensional layout of a scene, and the other representing the two-dimensional perspective view of the scene from a given vantage point.     

Police officers' credibility judgments: Accuracy and estimated ability

A study was conducted to examine Spanish police officers' and nonofficers' lie‐ and truth‐detection accuracy, as well as their estimated detection ability. The participants were 121 police officers and 146 undergraduates who watched videotaped truthful and deceptive statements. They had to indicate: (1) whether each statement was truthful or deceptive, and (2) how good police officers were, in comparison with the general population, at detecting the truthfulness or deceptiveness of a statement. Results indicate that police officers' accuracy was not higher than that of nonofficers, rather, while the officers reached an accuracy rate close to chance probability, the undergraduates surpassed that probability. Officers had a very strong tendency to judge the statements as deceptive; this made them less accurate than the students in judging the truthful accounts, while both groups reached a similar accuracy when judging the deceptive ones. Both occupational samples considered that the police are more capable of identifying truths and lies than the general population. However, this belief was stronger among the officers themselves than among the nonofficers. No significant correlation between estimated ability and accuracy was found for either sample. The results are explained in terms of the participants' wrong beliefs about the cues to deceit and the socialization process that police officers undergo, which would increase their confidence and perceived ability while hindering their learning of the actual indicators of deceit. The need for officers to receive training is emphasized, and some directions are given on how this training should be carried out.     

Accuracy of feeling-of-knowing judgments for predicting perceptual identification and relearning

The feeding of knowing refers to predictions about subsequent memory performance on previously nonrecalled items. The most frequently investigated type of subsequent performance has been recognition. The present research explored predictive accuracy with two new feeling-of-knowing criterion tests (in addition to recognition): relearning and perceptual identification. In two experiments, people attempted to recall the answers to general-information questions such as, "What is the capital of Australia?", then made feeling-of-knowing predictions for all nonrecalled answers, and finally had a criterion test to assess the accuracy of the feeling-of-knowing predictions. Experiment 1 demonstrated that perceptual identification can be employed successfully as a criterion test for the feeling of knowing. This opens a new way for metamemory research via perception. Moreover, the feeling-of-knowing accuracy for predicting perceptual identification was not significantly correlated with the feeling-of-knowing accuracy for predicting recognition, in accord with the idea that these two tests assess memory differently. Experiment 2 demonstrated that relearning performance can also be predicted by feeling-of-knowing judgments. Both experiments showed that there is a positive relationship between the feeling of knowing and the amount of time elapsing before a memory search is terminated during recall. Further analyses showed that this relationship is substantial for nonrecalled items for which the person did not guess an answer (omission errors), but the relationship is null or negative for nonrecalled items that the person guessed incorrectly (commission errors). Several theoretical mechanisms that may underlie the feeling of knowing are proposed.     

Impact of planned movement direction on judgments of visual locations

The present study examined if and how the direction of planned hand movements affects the perceived direction of visual stimuli. In three experiments participants prepared hand movements that deviated regarding direction (“Experiment 1” and “2”) or distance relative to a visual target position (“Experiment 3”). Before actual execution of the movement, the direction of the visual stimulus had to be estimated by means of a method of adjustment. The perception of stimulus direction was biased away from planned movement direction, such that with leftward movements stimuli appeared somewhat more rightward than with rightward movements. Control conditions revealed that this effect was neither a mere response bias, nor a result of processing or memorizing movement cues. Also, shifting the focus of attention toward a cued location in space was not sufficient to induce the perceptual bias observed under conditions of movement preparation (“Experiment 4”). These results confirm that characteristics of planned actions bias visual perception, with the direction of bias (contrast or assimilation) possibly depending on the type of the representations (categorical or metric) involved.     

Vertical disparity affects shape and size judgments across surfaces separated in depth

Vertical binocular disparity provides a useful source of information allowing three-dimensional (3-D) shape to be recovered from horizontal binocular disparity. In order to influence metric shape judgments, a large field of view is required, suggesting that vertical disparity may play a limited role in the perception of objects projecting small retinal images. This limitation could be overcome if vertical disparity information could be pooled over wide areas of 3-D space. This was investigated by assessing the effect of vertical disparity scaling of a large surround surface on the perceived size and 3-D shape of a small, central object. Observers adjusted the size and shape of a virtual, binocularly defined ellipsoid to match those of a real, hand-held tennis ball. The virtual ball was presented at three distances (200, 325, and 450 mm). Vertical disparities in a large surround surface were manipulated to be consistent with a distance of 160 mm or infinity. Both shape and size settings were influenced by this manipulation. This effect did not depend on presenting the surround and target objects at the same distance. These results suggest that the influence of vertical disparity on the perceived distance to a surface also affects the estimated distance of other visible surfaces. Vertical disparities are therefore important in the perception of metric depth, even for objects that in themselves subtend only small retinal images.     

Selectivity, scope, and simplicity of models: a lesson from fitting judgments of perceived depth.

When comparing psychological models a researcher should assess their relative selectivity, scope, and simplicity. The third of these considerations can be measured by the models' parameter counts or equation length, the second by their ability to fit random data, and the first by their differential ability to fit patterned data over random data. These conclusions are based on exploration of integration models reflecting depth judgments. Replication of Massaro's (1988a) results revealed an additive model (Bruno & Cutting, 1988), and Massaro's fuzzy-logical model of perception (FLMP) fit data equally well, but further exploration showed that the FLMP fit random data better. The FLMP's successes may reflect not its sensitivity in capturing psychological process but its scope in fitting any data and its complexity as measured by equation length.     

Hens use occlusion to judge depth in a two-dimensional picture

Hens (Gallus gallus domesticus) were taught to peck at a touch screen. On the screen was a grid on which a square and a circle were depicted. The square and the circle were given different positions at random for each trial, but were never overlapping. The hens were rewarded for pecking at the symbol that was higher up on the grid/screen, i.e. at the one that to a human observer was seen as being further away. Every tenth trial was a probe trial in which the animals were presented with either the circle overlapping the square or vice versa. The hens were never rewarded during the probe trials. As mentioned, the hens had learned to peck at the symbol that appeared to be further away during the nonprobe trials. During the probe trials the hens pecked at the symbol that was occluded, i.e. in the absence of any other cues they used occlusion to determine which of the two symbols was further away. The results suggest that not only can nonhuman animals use image height as a cue but that they can generalise this to situations in which occlusion is the only depth cue present.     

Comparing the sensitivity of manual pursuit and perceptual judgments to pictorial depth effects

Abstract - We examined whether a pictorial depth illusion influences the manual pursuit of a moving dot to the same extent that it influences the dot's apparent displacement. Fourteen subjects performed two tasks. In one case, they used their unseen hand to track a dot that moved on an elliptical path. In the other, they first watched the dot move on the same path, and then set an ellipse to match the shape of the dot's path. The illusion influenced the two tasks to the same extent, suggesting that the visual information processing is the same for the two tasks.     

Integration of disparity and velocity information for haptic and perceptual judgments of object depth

Do reach-to-grasp (prehension) movements require a metric representation of three-dimensional (3D) layouts and objects? We propose a model relying only on direct sensory information to account for the planning and execution of prehension movements in the absence of haptic feedback and when the hand is not visible. In the present investigation, we isolate relative motion and binocular disparity information from other depth cues and we study their efficacy for reach-to-grasp movements and visual judgments. We show that (i) the amplitude of the grasp increases when relative motion is added to binocular disparity information, even if depth from disparity information is already veridical, and (ii) similar distortions of derived depth are found for haptic tasks and perceptual judgments. With a quantitative test, we demonstrate that our results are consistent with the Intrinsic Constraint model and do not require 3D metric inferences (Domini, Caudek, & Tassinari, 2006). By contrast, the linear cue integration model (Landy, Maloney, Johnston, & Young, 1995) cannot explain the present results, even if the flatness cues are taken into account.